The symbiosis between rhizobial bacteria and legume plants has served as a model for investigating the genetics of nitrogen fixation and the evolution of facultative mutualism. We used deep sequence coverage (>100×) to characterize genomic diversity at the nucleotide level among 12 Sinorhizobium medicae and 32 S. meliloti strains. Although these species are closely related and share host plants...

Biological nitrogen fixation is an important source of fixed nitrogen for the biosphere. Microorganisms catalyse biological nitrogen fixation with the enzyme nitrogenase, which has been highly conserved through evolution. Cloning and sequencing of one of the nitrogenase structural genes, nifH, has provided a large, rapidly expanding database of sequences from diverse terrestrial and aquatic env...

Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its ...

Using the general concept of a dry multilayer analytical element, we can change chemical procedures and configurations to assay several blood components. In the assay of serum urea nitrogen, urease in the reagent layer catalyzes the hydrolysis of urea. A semipermeable membrane excludes aqueous base, but allows ammonia to diffuse to an underlying indicator layer. For the amylase determination, t...

doi: 10.1111/j.1399-3054.2006.00716.x Highly sensitive techniques for transcriptome analysis, such as microarrays, complementary DNA-amplified fragment length polymorphisms (cDNAAFLPs), and others currently used in functional genomics require a high RNA quality and integrity, as well as reproducibility among extractions of replicates from the same tissue. There are, however, few technical paper...

Eller, Charles (St. John's University, Jamaica, N.Y.), and William H. Beckert. Nitrogen dioxide fixation in bacterial chromatin studies. J. Bacteriol. 90:1710-1712. 1965.-Satisfactory chromatin staining was obtained with two Bacillus species when nitrogen dioxide was used for fixation in conjunction with either the acid Giemsa or Feulgen staining methods. An impression method was employed for t...

Heat and shock sensitive tosyl azide was generated and used on demand in a telescoped diazo transfer process. Small quantities of tosyl azide were accessed in a 'one pot' batch procedure using shelf stable, readily available reagents. For large scale diazo transfer reactions tosyl azide was generated and used in a telescoped flow process, to mitigate the risks associated with handling potential...

Persimmon-like NaLa(WO(4))(2) microarchitectures were prepared via hydrothermal process with using trisodium citrate (Na(3)Cit) as chelated reagent and characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), photoluminescence (PL), and fluorescent dynamics. The influences of Na(3)Cit concentration, organic additivities, and reaction time on the morphologi...

The proton transfer channel for the reaction of HBr + with HBr is investigated in a state-specific manner by preparing the reagent ion in a selected internal state by resonance-enhanced ionization (REMPI) and monitoring the disappearance of this ion by laser-induced fluorescence (LIF). A rate constant for proton transfer of (6.7 + 1.6) × 10-10 cm3/s is found. The reaction of HBr + with HBr and ...

Abstract. We present the development of a chemical ionization mass spectrometer ion source specifically designed for in situ measurements trace gases upper troposphere and lower stratosphere. The utilizes commercially available photoionization krypton lamp, primarily emitting photons vacuum ultraviolet (VUV) region at wavelengths 124 117 nm (corresponding to energies 10 10.6 eV, respectively), ...